Federal investigators bought a Detroit barbershop, hired a barber and opened for business, all as part of an undercover sting operation.

Exclusive video shows dangerous men selling dangerous weapons at the barbershop. Stolen hand guns, machine guns, sawed-off shot guns and even hand grenades were among the weapons. The criminals do not seem to care that the guns will be used in violent crimes that kill kids and parents. They just want the cash.

It's no secret Detroit has a serious violent crime problem. In 2012, 386 people were murdered in the city, of which 80 percent of the victims were shot to death. Most were under the age of 30. Add 1,200 non-fatal shootings and it becomes beyond obvious that gun violence is out of control.

Drastic times call for drastic measures

In a drastic effort to get the guns off the street, the Bureau of Alcohol, Tobacco, Firearms and Explosives went into the barbershop business. They purchased the shop in one of Detroit's most violent neighborhoods and started cutting hair.

"It gave the business a legitimacy in the neighborhood," said an undercover federal agent.

As they trimmed beards and cut hair they let it be known that they were in the weapons market. The Local 4 Defenders have spoken with actual undercover agents involved in the case.

"We set up a barbershop, opened the doors up, worked four days a week for a few hours a day. At that time people who were just coming off the offered to sell us guns," said an agent.

Within days, dozens of customers started showing up at the shop, opting to skip the haircut and instead head straight into the back office with weapons to sell.

Most of the guns were stolen. They didn't seem to care that selling guns on the street is against the law. They were focused on the cash.

"Yeah, a lot of individuals would actually carry long guns up to the location -- long guns, shot guns, long gun rifles -- they would stick them down their pant leg and walk in with them," said an undercover agent.

Agents say the sales started immediately.

"I want to say within the first day or two when we were open an individual walked into our doors with a sawed-off shot gun and asked if we wanted to purchase it," an agent said. "I was surprised nobody ever saw them walking down the sidewalk or down the street with a firearm sticking out of their pants."

Usually, agents go to gun dealers. However, things were so bad in this neighborhood they took the unusual step of having gun sellers come to them. After all, who would think the ATF would buy a barbershop and hire a barber just to but people selling illegal guns? The boss says drastic times call for drastic measures.

"These operations are important due to the fact that they're able to remove the most violent offenders from the community, thereby making communities much safer," said Daryl McCray, acting special agent in charge at Detroit ATF.

"It's our location so we decide when we want to meet somebody or decide if we do not want to meet somebody," said an agent.

Community sees positive impact

Dozens of weapons were pulled off the streets. Those who were selling them were arrested and sent to prison.

"We spend a lot of time -- our business model at ATF is patterned around identifying the most violent offenders, or trigger pullers, as we call them," said an agent.

The Local 4 Defenders cannot identify the exact location of the barbershop but can say residents in the area are seeing a difference. Dozens of the men they feared most now are locked up.

A real business now is operating in the space, providing goods to locals in a safer environment.

To report illegal activity or stolen weapons, go to the ATF's website.